Study on characteristics of filamentary and glow discharges generated at atmospheric dielectric barrier discharge

An atmospheric dielectric barrier discharge was generated using (50-120) kHz sinusoidal voltage waveform. On one side of the electrode, a transparent electrode was used for observing the plasma cross section with a CCD camera. It was found that whether the discharge is glow or filamentary was determined by the applied voltage, and noticeable differences were observed between filamentary and glow discharges. In the filamentary discharge, the temporal position of the current peak and the spatial position of the filaments were almost fixed. Number of filaments increased as the applied voltage. It was also found that the transition from filamentary discharge to glow discharge was rather discontinuous. The intensity of the plasma emission increased with the electrical charge. Using Ar, He, and He-O₂ mixed gas, dependence of the discharge characteristics on the gas type was investigated. Paschen curve was obtained at various operation conditions as a function of frequency and gap distance.